The present invention relates to a gas control valve which uses an activation member made from memory alloy to control movement of a rod which is engaged with a gas passage in a gas burner.
A conventional gas control valve is shown in FIG. 1 and generally includes two blocks 10 overlapped with each other, and a mediate plate 11 is clamped between the two blocks 10. A gas path 13 is defined between the two blocks 10 and the mediate plate 11 has a passage 12 defined therethrough which communicates with the gas path 13. An adjusting bolt 14 is movably inserted in one of the two blocks 10 and a tip of the adjusting bolt 14 is engaged with said passage 12 so that the user may rotate the adjusting bolt 14 to control a gap between the tip of the adjusting bolt 14 and the passage 12. By this way, the volume of the gas passing through the passage 12 can be controlled. It requires a tool to adjust the adjusting bolt 14 and the adjusting bolt 14 is usually located in an inside of the burners so that the users are not encouraged to do the job.
It is the primary objective of the present invention to provide a structurally simple gas control valve that normally allows gas to flow and when subject to heat blocks the gas.
According to the present invention, a gas control, valve includes a first element, a second element, a mediate element, a sleeve, a rod and a control element. The first element defines a first path. The second element defines a second path and a hole in communication with the second path. The mediate element defines a passage. The mediate element is sandwiched between the first and second elements so that the first path is in communication with the second path through the passage. The sleeve includes a first end and a second end. The first end of the sleeve is inserted into the hole. The rod includes a first end and a second end. The rod is inserted into the sleeve so that the first end of the rod is inserted into the second path and that the second end of the rod is exposed through the second end of the sleeve. The control element is connected between the second end of the sleeve and the second end of the rod. Normally, the control element keeps the rod in a first position wherein the first end of the rod opens the passage. When subjected to heat, the control element moves the rod to a second position wherein the first end of the rod closes the passage.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.